The synapse is a mechanism that allows amazingly rapid communication between cells, and I don't see any major leap between co-opting an ensemble of proteins that senses the environment for sensing of signals from other cells.

It’s like the magic sword, a grunt’s Excalibur: all you do is move that finger so imperceptibly just a wish flashing across your mind like a shadow, not even a full brain synapse, and I poof in a blast of sound and energy and light a truck or a house or even people disappear, everything flying and settling back into dust.

When it has been “excited” by the chemical messengers, the connection between two nerve cells is strengthened, or potentiated—that is, the synapse learns to fire in this way, and in the future it becomes easier and easier to do so.